Lubricating oils for automotive and diesel engines have changes over the years. Today's engines are designed to run hotter and harder than in the past. Various additives have been used in lubricant formulations in order to reduce friction between moving parts and reduce engine wear. Such additives include organo-molybdenum additives and organo-zinc phosphate additives. While such additives are particularly useful as friction and wear reducers modifiers, such additives may have one or more of the following disadvantages: poor oil solubility; copper and/or lead corrosion; color darkening of the finished lubricant; and increased levels of sulfur and/or phosphorus in the finished lubricant.
Future generations of passenger car motor oils and heavy duty diesel engine oils require lower levels of phosphorus and sulfur in the finished oil in order to protect pollution control devices as it is well known that sulfur and phosphorus containing additives may poison or otherwise reduce the effectiveness of pollution control devices. For example, current GF-4 motor oil specifications require a finished oil to contain less than 0.08 wt % and 0.7 wt % phosphorus and sulfur, respectively, and PC-10 motor oil specifications, the next generation heavy duty diesel engine oil, requires oils to contain less than 0.12 wt % and 0.4 wt % phosphorus and sulfur, respectively, and 1.0 wt % sulfated ash. Certain molybdenum and organo-zinc additives known in the industry contain phosphorus and sulfur at levels which reduce the effectiveness of pollution control devices.
Therefore, a need exists for lubricant additives and compositions that provide enhanced friction and wear reducing properties and which are more compatible with pollution control devices used for automotive and diesel engines. A need also exists for such lubricant additives and compositions which are more compatible with such pollution control devices without adversely affecting oil solubility, corrosion, and/or darkening the color of the finished lubricant. Hydrocarbon soluble organo-titanium compounds are believed to be useful for reducing the amount of molybdenum and/or organo-zinc compounds used in lubricating oil formulations while achieving similar or improved results without adversely affecting pollution control devices on the engines.
The use of organo-titanium compounds typically includes a multi-step synthesis process, purification, and blending of the compounds into additive concentrates and lubricant formulations. However, the foregoing process is time-consuming thus expensive. What is needed is a relatively simple process for making a titanium-containing additive in-situ in a concentrate that can be directly added to an oil of lubricating viscosity.
With regard to the foregoing, exemplary embodiments of the disclosure provide a method for making a titanium-containing lubricant additive, a lubricant additive concentrate made by the method and a lubricating composition containing the additive concentrate. According to embodiments of the disclosure, the method includes reacting titanium alkoxide with water in a reaction medium that includes a dispersant to provide a homogeneous titanium-containing additive product. The additive product made by the method is substantially devoid of acidic components.
Another exemplary embodiment of the disclosure provides a titanium additive product for a lubricating oil. The additive product includes a titanium product made by a process of reacting titanium alkoxide with water in a reaction medium including a dispersant at a temperature ranging from about 25° to about 140° C. to provide a homogeneous titanium-containing additive product. The additive product in a base oil is no more corrosive than the base oil devoid of the additive product as determined by a high temperature corrosion bench test.
An advantage of the embodiments of the disclosure is that a substantially precipitate free product may be formed. The product is believed to be less corrosive in lubricating oil formulations since the product is not made using acidic reactants. Blending of the product with other components of a lubricating oil composition may be more precise due to an absence of visible particles and precipitates in the additive product as made. Other features and advantages of the disclosed embodiments may be provided by the following detailed description.